THVD1406: Data Rate

Hi Francis,

I would consult this document which shows the THDV1426 transceiver at lower data rates, and it gives good suggestions: https://www.ti.com/lit/an/slla574/slla574.pdf 

Technically, THVD1405 will likely have issues at 9.6kbps since the RS-485 bus will be dominant for long periods of time such that the auto direction feature will kick in. However, this transceiver can support 250,000 Kbps just fine. If they add failsafe resistors (pullup on A/pulldown on B), it might allow them to communicate at lower data rates. 

Best,

Ethan

Hi Francis,

We do not specify a minimum data rate for this device. However, I would recommend a data rate that has dominant times shorter than 8us (which is the typical auto direction time). If you add failsafe resistors to the bus like that app note recommends, you can likely use 125,000kbps.

Best,

Ethan 

Hi Francis,

At 9.6Kbps, even failsafe resistors will likely not work. However, the customer can test this on their own if they are desperate. 

Currently we only have 2 transceivers with the auto-direction feature: THVD1406 and THVD1426. So there are no other options. 9.6Kbps is quite low for RS-485, the lowest standard speed is ~125Kbps. 

Best,

Ethan